Archaeometallurgy in Messina: Iron Slag from a Dig at Block P, Laboratory Analyses and Interpretation
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49 Mediterranean Archaeology and Archaeometry, Vol. 8, No. 1, pp. 49-60 Copyright © 2008 MAA Printed in Greece. All rights reserved. ARCHAEOMETALLURGY IN MESSINA: IRON SLAG FROM A DIG AT BLOCK P, LABORATORY ANALYSES AND INTERPRETATION Ingoglia Caterina 1, *, Triscari Maurizio 2, Sabatino Giuseppe 2 1Regional Museum of Messina, Viale della Libertà, 98100 Messina (e-mail: [email protected]) 2Department of Earth Sciences, University of Messina – Salita Sperone 31, 98166 Messina- Sant’Agata (ME) Received 15/6/2007 * to whom all correspondence should be addressed Hccepted 20/12/2007 ABSTRACT The archaeological site in Via La Farina, Block P, in Messina, is unique in many ways, due also to the high quantity of samples of iron slag. The slag was examined to identify the production centres of such materials, and, after characterization, was compared to similar material, exclusively for product typology, from different archaeological sites in the province of Messina, situated in the Peloritani Mountains (Messina city, S. Marco d'Alunzio, Milazzo, Francavilla di Sicilia, Novara di Sicilia as well as the archaeological site of Halaesa, near Tusa). Mineralogical characterization of the phases carried out by X-ray diffractometry (XRD) and Rietveld data elaboration, morphological study of slag findings and a semi-quantitative analysis by scanning electronic microscope (SEM+EDX) were performed. A chemical investigation was carried out by electron probe micro analysis (EPMA), to determine major element,. Minor and trace elements were determined by LA-ICP-MS. All the examined slag is related to iron metallurgy, and, in the case of Via La Farina, there is firm archaeological evidence pinpointing to smelting activity. KEYWORDS : iron slag, Messina, archaeometallurgy, XRD, EPMA, LA-ICP-MS 50 INGOGLIA CATERINA et al INTRODUCTION 2007), revealed an extraordinary concentration of iron slag (fig. 1), The archaeological excavation inside a ditch (US 56) located in the carried out in Messina in western part of the area under compartments 90-91 of Block P, investigation. between 2003 and 2004 (Ingoglia Fig. 1 General plan phase 3 of period 3 It is certain that the find consists of reasonably considered the most ancient some waste products from iron works excavated in Sicili (for other which were thrown into the hole, mineralogical, petrografic and chemical together with other observed material analyses on archaeological finds, used as charge flux prepared for burning ceramics, from Messina, Bacci et al. 2006) (shells, animal bones). The activity was Thinking that the potential probably linked to a furnace, the exact information which could be gleaned whereabouts of which is still unknown, from the slag might be of great use in but which was certainly not far from the better defining the area under area studied by our team of investigation, and above all, in an archaeologists. All the area surrounding attempt to reconstruct techniques and the ditch is in fact full of clues which methods of metal production in would indicate a metallurgical Messina in the Classic Greek age, it workshop, which, as we shall see, dating was decided to undertake a study back to the 5 th century BC, can be based on archaeometric analyses. ARCHAEOMETALLURGY IN MESSINA 51 Some slag samples were analysed period (ca.480-450 B.C.), a siderurgical in order to determine the metal origin workshop was set up in the zone, from through observation of composition which some pieces were found in a and chemical features. Given the waste ditch. Some work areas were archaeological context of origin, and also identified, but we have not been being aware of the potential able to determine the exact nature of importance of a new discovery, an the work carried out, given the effort was made to understand the reduced size of the excavated area. pyrometallurgical processes under- The stratigraphic archaeological gone by the metal, also taking into investigation identified three phases of account evidence found in literature, activity in the life of the workshop, in which traditionally attributes parti- the same third period and all dateable, cular metallurgical skills to the on the basis of pottery in the layers, to inhabitants of Calcide from Eubea, just before or around the mid-5th cent. homeland of Zancle, the ancient name BC. Excavation activities have been of Messina. recorded in different S tratigraphic Units, further on identified as “US”. ARCHAEOLOGICAL DATA Two ditches relate to the first phase (US 164 and US 160), both excavated Archaeological findings from the in a sand deposit (US 167) and linked dig in the area investigated have by a channel (US 169). The finding, in allowed us to identify five distinct ditch US 160, of two layers of filler periods with activity, and two of material, superimposed and rich in abandonment, distributed over a time iron slag, was vital in identifying the span from 7 th cent. to the mid-4 th area as a workshop, and, in particular, century BC ca. in conferring a waste function to ditch In particular, it was possible to US 160 (fig. 2). determine that, during the third Fig. 2. West wall section of US 56 and US 160 52 INGOGLIA CATERINA et al The deepest landfill, US 154, previous one, related to phase 1, consisted of dark, carbonaceous earth, below the said floor (US 56). The with a lot of iron slag and a quantity filling in the ditch is made up of a of shells; it was covered by US 136, not thick layer of black earth, rich in iron as thick (ca. 8 cm), but rich in iron slag (11 crates were filled) slag, which explains the reddish representing the entire US 134. This colour of the earth, and also with a covered a lighter-coloured layer (US very high quantity of shells on the 135) with a high quantity of surface. On the western side of the punctiform, carbonaceous traces and hole, there are two small layers of a pottery, often darkened only lighter coloured, ferrous earth, US 159 externally, mixed in with iron slag, but and US 161, with no trace of any in much lower quantities compared to archaeological material. US 134. Both US 134 and 135 of phase Ditch US 164 was filled with silty 3 and US 136 of phase 1 contained sand, with very few archaeological many shells. findings (US 163) and the entire area A small tank (US 131) also belongs was covered by a layer of sandy silt to phase 3, found in the eastern part of (US 156 that is, for color and the dig, with walls, fragmented in the composition, the same as US 157). upper part, covered with refractory US 141, part of a wall, belongs to clay (fig. 3). The function of the small phase 2. The wall ran in an east-west tank is uncertain. It was filled with direction and was covered, to the earth (US 132) with hardly any south, by tile fragments, which very archaeological material, and a block of probably marked a tank which can conglomerate, probably formed now be seen in US 156 (US 148) inside naturally. We were unable to of which, the liquid, which ran in the ascertain if it could have been used in terracotta channel US 146, cutting US some way in the activity of the 141 perpendicularly, most likely workshop. flowed. (Caterina Ingoglia) Later, both ditches were filled with dark, silty earth, very rich in archaeological material (US 149 and US 166) dateable to around mid-5 th cent. BC. All the area was sealed by a lighter-coloured heap of earth (US 127 is the same as US 129). Phase 3 is distinguished by the finding of a workshop floor (US 86) made up of a bed of pebbles and iron slag, about cm 3.00/3.50 thick, over which lime was cast making the floor suitable for treading (see, fig. 1), and Fig.3. US 131 by a new waste ditch, bigger than the ARCHAEOMETALLURGY IN MESSINA 53 DESCRIPTION OF THE IRON Halaesa, near Tusa) - was also taken SLAG ANALYSED: into account (Barone et al. 2005, TYPOLOGICAL DISTINCTION Bonanno et al. 1998; Sabatino et al Some previous isolated works on 2004; Triscari et al. 2006). ferriferous slag found in sites of north- eastern Sicily, have provided information on existing relationships between the various typologies of metalliferous slag found and metallogenesis in the Peloritani mountains. This is related, above all, to two distinct events which can both be found in low-medium grade metamorphites. The first event refers to pre- metamorphic and pre- Hercynian Fig. 4 Some of the exhamined iron slag “strata-bound”, mineralized bodies, from the Blok P site in Messina. characterized by simple Fe, Pb and Zn sulphides: the second event is LABORATORY ANALYSES: characterized by mineral bodies of distinct veins, linked to a METHODOLOGY hydrothermal system, and associated After a precise selection and with local, late-Hercynian preparation of samples, preliminary metamorphic events, represented stereoscopic tests were carried out principally by complex, Cu, Pb, Sb, under the microscope. Slides were As, and Bi sulphide mineralization. then prepared for a reflected polarized The archaeological site in Via La light metallographic test. Farina, in Messina, is unique in many Mineralogical characterization of the ways, due also to the high quantity of phases was carried out by X-ray samples of iron slag analysed. Most of diffractometry (XRD) and Rietveld the material was taken from method. Morphological study of slag stratigraphic unit US 134 (fig. 4) and, findings and a semi-quantitative after characterization, was compared analysis were performed by scanning to similar material exclusively for electronic microscope (SEM+EDX, product typology. The fact that the Dept. of Earth Sciences, Univ.